Water effect on the interaction between amylose and amylopectin during retrogradation

Possible interactions between amylose (AM) and amylopectin (AP) during a temperature cycled retrogradation (4/30°C 1 day at each temperature, 2 days) in aqueous pastes/gels of corn starch and reconstituted mixtures of AM and AP (1:3 weight ratio) were examined at different water levels (60-90%). With the pastes containing 90% water, no AP crystallization was observed under a differential scanning calorimeter in waxy starch or the starches containing AM. With 80% water, AP crystallization was not observed in waxy starch but it was found in the starches containing AM. With 70% water, AP crystallization was facilitated by the presence of AM. With 60% water, however, AP crystallization was found not to be affected by AM presence. It was evident that the presence of AM (25%) affected AP crystallization during retrogradation but only when the water content in starch pastes/gels was proper (70-80% in this study).